Film deposition apparatus

ABSTRACT

A film deposition apparatus includes a process chamber, a rotary table, a first reaction gas supply part disposed in a first process region and configured to supply a first reaction gas, a second reaction gas supply part disposed in a second process region apart from the first reaction gas supply part in a circumferential direction of the rotary table and configured to supply a second reaction gas, and separation gas supply parts disposed in a separation region between the first reaction gas supply part and the second reaction gas supply part and configured to supply a separation gas for separating the first reaction gas and the second reaction gas. The separation gas supply parts are configured to supply, in addition to the separation gas, an additive gas for controlling adsorption of the first reaction gas or for etching a part of material components included in the first reaction gas.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is based upon and claims the benefit of priorityof Japanese Patent Application No. 2016-102231, filed on May 23, 2016,the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

An aspect of this disclosure relates to a film deposition apparatus.

2. Description of the Related Art

In a known film deposition method, hydroxyl groups are formed on aninner surface of a recess formed in a substrate, an organic aminosilanegas is supplied and caused to be adsorbed to the substrate on which thehydroxyl groups are formed, and an oxidizing gas is supplied to thesubstrate to which the organic aminosilane gas is adsorbed to form asilicon oxide film on the inner surface of the recess (see, for example,Japanese Laid-Open Patent Publication No. 2013-135154).

In this film deposition method, the substrate on which hydroxyl groupsare formed is exposed to oxygen plasma to cause a part of the hydroxylgroups to be desorbed and thereby control the distribution of thehydroxyl groups. For example, this method makes it possible to perform afilm deposition process with high bottom-up capability and to form afilm that is conformal to the shape of the recess.

With the above film deposition method, however, hydroxyl groups desorbedas a result of the exposure to the oxygen plasm may spread along withthe flow of a gas and adhere again to the surface of the silicon oxidefilm. If hydroxyl groups adhere again to the surface of the siliconoxide film, the distribution of hydroxyl groups on the surface of thesubstrate becomes uneven, and the in-plane uniformity of a film formedon the substrate decreases.

SUMMARY OF THE INVENTION

In an aspect of this disclosure, there is provided a film depositionapparatus including a process chamber, a rotary table that is disposedin the process chamber and includes an upper surface for holding asubstrate, a first reaction gas supply part that is disposed in a firstprocess region above the rotary table and configured to supply a firstreaction gas to the upper surface of the rotary table, a second reactiongas supply part that is disposed in a second process region apart fromthe first reaction gas supply part in a circumferential direction of therotary table and configured to supply a second reaction gas, whichreacts with the second reaction gas, to the upper surface of the rotarytable, and separation gas supply parts that are disposed in a separationregion between the first reaction gas supply part and the secondreaction gas supply part in the circumferential direction of the rotarytable and configured to supply a separation gas for separating the firstreaction gas and the second reaction gas, the separation gas supplyparts being arranged at predetermined intervals along a radial directionof the rotary table. The separation gas supply parts are configured tosupply, in addition to the separation gas, an additive gas forcontrolling adsorption of the first reaction gas or for etching a partof material components included in the first reaction gas.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a film deposition apparatusaccording to an embodiment;

FIG. 2 is a perspective view of an internal configuration of a vacuumchamber of the film deposition apparatus of FIG. 1;

FIG. 3 is a plan view of the internal configuration of the vacuumchamber of the film deposition apparatus of FIG. 1;

FIG. 4 is a cross-sectional view of a separation region of the filmdeposition apparatus of FIG. 1;

FIG. 5 is a cross-sectional view of the vacuum chamber taken along aconcentric circle of a rotary table of the film deposition apparatus ofFIG. 1;

FIG. 6 is another cross-sectional view of the film deposition apparatusof FIG. 1;

FIG. 7 is a cross-sectional view of a plasma generator of the filmdeposition apparatus of FIG. 1;

FIG. 8 is another cross-sectional view of the plasma generator of thefilm deposition apparatus of FIG. 1;

FIG. 9 is a top view of the plasma generator of the film depositionapparatus of FIG. 1;

FIGS. 10A and 10B are drawings illustrating flow distribution andconcentration distribution of an H₂ gas in a separation region;

FIGS. 11A and 11B are drawings illustrating flow distribution andconcentration distribution of an H₂ gas in a separation region;

FIGS. 12A and 12B are drawings illustrating flow distribution andconcentration distribution of an H₂ gas in a separation region;

FIGS. 13A and 13B are drawings illustrating flow distribution andconcentration distribution of an H₂ gas in a separation region; and

FIG. 14 is a graph illustrating a relationship between the supply flowrate of an H₂ gas and the thickness of a silicon oxide film formed on awafer.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the present invention are described below with referenceto the accompanying drawings. Throughout the specification and thedrawings, the same reference number is assigned to substantially thesame components, and repeated descriptions of those components areomitted.

<Film Deposition Apparatus>

A film deposition apparatus according to an embodiment is describedbelow. FIG. 1 is a cross-sectional view of the film deposition apparatusaccording to the present embodiment. FIG. 2 is a perspective view of aninternal configuration of a vacuum chamber of the film depositionapparatus of FIG. 1. FIG. 3 is a plan view of the internal configurationof the vacuum chamber of the film deposition apparatus of FIG. 1.

As illustrated by FIGS. 1 through 3, the film deposition apparatus mayinclude a vacuum chamber 1 having a substantially circular planar shape,and a rotary table 2 that is disposed in the vacuum chamber 1 such thatthe center of the vacuum chamber 1 matches the center of rotation of therotary table 2. The vacuum chamber 1 is a process chamber where a filmis formed on a wafer. The vacuum chamber 1 may include a chamber body 12shaped like a closed-end cylinder and a top plate 11 that ishermetically and detachably attached via a sealing part 13 (FIG. 1) suchas an O-ring to the upper surface of the chamber body 12.

A central portion of the rotary table 2 is fixed to a cylindrical core21, and the core 21 is fixed to an upper end of a rotational shaft 22that extends in the vertical direction. The rotational shaft 22 passesthrough a bottom 14 of the vacuum chamber 1, and a lower end of therotational shaft 22 is attached to a drive unit 23 that rotates therotational shaft 22 about a vertical axis. The rotational shaft 22 andthe drive unit 23 are housed in a tubular case 20 with an opening at theupper end. A flange formed at the upper end of the case 20 ishermetically attached to a lower surface of the bottom 14 of the vacuumchamber 1 so that the internal atmosphere of the case 20 is isolatedfrom the external atmosphere.

As illustrated in FIGS. 2 and 3, multiple (five in this example)recesses 24 for holding substrates or semiconductor wafers (which arehereafter referred to as “wafers W”) are formed in an upper surface ofthe rotary table 2. The recesses 24 have a substantially circular shapeand are arranged along the rotational direction (or the circumferentialdirection) of the rotary table 2. In FIG. 3, for brevity, the wafer W isillustrated only in one of the recesses 24. Each recess 24 has an insidediameter that is slightly (e.g., 4 mm) greater than the diameter of thewafer W, and has a depth that is substantially the same as the thicknessof the wafer W. Accordingly, when the wafer W is placed in the recess24, the height of the upper surface of the wafer W becomes substantiallythe same as the height of the upper surface (in an area where no recess24 is formed) of the rotary table 2. Through holes (not shown) areformed in the bottom of each recess 24. For example, three elevatingpins pass through the through holes to support the lower surface of thewafer W and move the wafer W up and down.

FIGS. 2 and 3 illustrate the internal configuration of the vacuumchamber 1. For illustration purposes, the top plate 11 is omitted inFIGS. 2 and 3. As illustrated by FIGS. 2 and 3, a reaction gas nozzle31, a reaction gas nozzle 32, a reaction gas nozzle 33, and separationgas supply parts 41 and 42 are arranged at intervals along thecircumferential direction of the vacuum chamber 1 (a direction indicatedby an arrow A in FIG. 3). In this example, the reaction gas nozzle 33,the separation gas supply parts 41, the reaction gas nozzle 31, theseparation gas supply parts 42, and the reaction gas nozzle 32 arearranged clockwise (along the rotational direction of the rotary table2) in this order from a transfer opening 15. The reaction gas nozzle 31,the reaction gas nozzle 32, and the reaction gas nozzle 33 may be formedof, for example, quartz. The separation gas supply parts 41 and 42 areformed in protruding parts 4 described later. The reaction gas nozzles31, 32, and 33 are inserted through an outer wall of the chamber body 12into the vacuum chamber 1 such that the reaction gas nozzles 31, 32, and33 extend in the radial direction of the chamber body 12 in parallelwith the upper surface of the rotary table 2. Gas introduction ports 31a, 32 a, and 33 a at the ends of the reaction gas nozzles 31, 32, and 33are fixed to the outer wall of the chamber body 12.

In the present embodiment, as illustrated in FIG. 3, the reaction gasnozzle 31 is connected via a pipe 110 and a flow rate controller 120 toa first reaction gas supply source 130. The reaction gas nozzle 32 isconnected via a pipe 111 and a flow rate controller 121 to a secondreaction gas supply source 131. The reaction gas nozzle 33 is connectedvia a pipe 112 and a flow rate controller 122 to a third reaction gassupply source 132. Five separation gas supply parts 41 are arranged inthe radial direction of the rotary table 2, and five separation gassupply parts 42 are arranged in the radial direction of the rotary table2. Details of the separation gas supply parts 41 and 42 are describedlater. The number of each of the separation gas supply parts 41 and theseparation gas supply parts 42 may also be less than or equal to four orgreater than or equal to six. However, the number of each of theseparation gas supply parts 41 and the separation gas supply parts 42 ispreferably greater than or equal to three, and is more preferablygreater than or equal to five to easily control the in-plane uniformityof the thickness of a film formed on the wafer W. Also in FIG. 3, theseparation gas supply parts 41 are placed in the same position in therotational direction of the rotational table 2, and the separation gassupply parts 42 are placed in the same position in the rotationaldirection of the rotational table 2. However, the separation gas supplyparts 41 may be placed in different positions in the rotationaldirection of the rotational table 2, and the separation gas supply parts42 may be placed in different positions in the rotational direction ofthe rotational table 2.

In each of the reaction gas nozzles 31, 32, and 33, multiple gasdischarge holes 35 are formed. The gas discharge holes 35 have openingsfacing the rotary table 2, and are arranged at an interval of, forexample, 10 mm along the longitudinal direction of each of the reactiongas nozzles 31, 32, and 33. With the gas discharge holes 35, thereaction gas nozzles 31, 32, and 33 can supply a first reaction gas, asecond reaction gas, and a third reaction gas, respectively, to theupper surface of the rotary table 2.

A region below the reaction gas nozzle 31 is a first process region P1where the first reaction gas is adsorbed onto the wafer W. A regionbelow the reaction gas nozzle 32 is a second process region P2 where thesecond reaction gas, which reacts with the first reaction gas adsorbedonto the wafer W in the first process region P1, is supplied to form amolecular layer of a reaction product. The molecular layer of thereaction product constitutes a film to be formed. A region below thereaction gas nozzle 33 is a third process region P3 where the thirdreaction gas is supplied to the reaction product (film) formed in thesecond process region P2 to modify the reaction product.

As necessary, a plasma generator 80 may be provided above the thirdprocess region P3. In FIG. 3, the plasma generator 80 is simplified andindicated by a dotted line. Details of the plasma generator 80 aredescribed later.

The first reaction gas may be any type of gas used as a material gas ofa film to be formed. For example, when a silicon oxide film (SiO₂ film)is to be formed, a silicon-containing gas such as organic aminosilane isselected as the first reaction gas. As another example, when a metaloxide film is to be formed, a reaction gas containing a metallic elementof the metal oxide film is selected as the first reaction gas. When atitanium oxide film (TiO₂ film) is to be formed as a metal oxide film, aTi-containing gas such as TiCl₄ is selected as the first reaction gas.

The second reaction gas may be any type of reaction gas that can reactwith the first reaction gas to form a reaction product. For example,when an oxide film such as an SiO₂ film or a metal oxide film is to beformed, an oxidizing gas is selected as the second reaction gas. Asanother example, when a nitride film such as a silicon nitride film (SiNfilm) or a metal nitride film is to be formed, a nitriding gas isselected as the second reaction gas. As more specific examples, when anSiO₂ film is to be formed, an O₃ gas may be selected; when a TiO₂ filmis to be formed, an H₂O or H₂O₂ gas may be selected; and when an SiNfilm or a TiN film is to be formed, an NH₃ gas may be selected.

The third reaction gas may be any type of modifying gas that canrearrange elements in a reaction product formed as a result of reactionbetween the first reaction gas and the second reaction gas, and therebyincrease the density of a film made of the reaction product. Forexample, when an SiO₂ film is to be formed, an Ar gas or a mixed gas ofan Ar gas and an O₂ gas is selected as the third reaction gas.

As illustrated in FIGS. 2 and 3, two protruding parts 4 are provided inthe vacuum chamber 1. The protruding parts 4 form separation regions D1and D2 together with the separation gas supply parts 41 and 42. Theprotruding parts 4 are attached to the lower surface of the top plate 11to protrude toward the rotary table 2. Each protruding part 4 has afan-like planar shape whose apex is cut off to form an arc. Theprotruding part 4 is disposed such that its inner arc is connected to aprotrusion 5 (described later), and its outer arc extends along theinner circumferential surface of the chamber body 12 of the vacuumchamber 1.

FIG. 4 is a cross-sectional view of the separation region D1 of the filmdeposition apparatus of FIG. 1 taken along the radial direction of therotary table 2.

As illustrated in FIG. 4, in one of the protruding parts 4, theseparation gas supply parts 41 are arranged at predetermined intervalsalong the radial direction of the rotary table 2. Each separation gassupply part 41 includes multiple gas discharge holes 41 h and a gasintroduction port 41 a communicating with the gas discharge holes 41 h.The gas discharge holes 41 h are arranged in the longitudinal directionof the separation gas supply part 41 (or the radial direction of therotary table 2). The gas introduction port 41 a is connected via a pipe114 and a flow rate controller 124 to a separation gas supply source134, and is also connected via a pipe 115 and a flow rate controller 125to an additive gas supply source 135.

The separation gas supply source 134 and the additive gas supply source135 supply a separation gas and an additive gas, respectively. Theseparation gas and the additive gas flow through the pipes 114 and 115,and the flow rates of the separation gas and the additive gas arecontrolled by the flow rate controllers 124 and 125, respectively. Then,the flow-rate-controlled separation gas and additive gas are suppliedvia the gas introduction port 41 a and the gas discharge holes 41 h intothe vacuum chamber 1. The supply flow rate of the separation gas and thesupply flow rate of the additive gas in the radial direction of therotary table 2 can be adjusted by separately controlling multiple flowrate controllers 124 and multiple flow rate controllers 125.

The additive gas may be any type of reaction gas that can control theadsorption of the first reaction gas, or any type of etching gas thatcan etch a part of material components included in the first reactiongas. The reaction gas that can control the adsorption of the firstreaction gas may either increase or decrease the adsorption of the firstreaction gas.

For example, when an SiO₂ film is to be formed, a hydrogen-containinggas is selected as the reaction gas to increase the adsorption of thefirst reaction gas. A hydrogen-containing gas forms OH groups on thesurface of SiO₂ that is a reaction product formed by the reactionbetween an Si-containing gas and an oxidizing gas, and increases theadsorption of the Si-containing gas. As the hydrogen-containing gas, forexample, an H₂ gas may be used. Other types of hydrogen-containing gasesmay also be used depending on purposes.

As another example, when a TiO₂ film is to be formed, ahalogen-containing gas such as a fluorine-containing gas or achlorine-containing gas is selected as the reaction gas to decrease theadsorption of the first reaction gas. A halogen-containing gas formsadsorption inhibitors on the surface of the wafer W to inhibit theadsorption of the first reaction gas to the wafer W. For example, ClF₃,F₂, NF₃, or CF₄ may be used as the fluorine-containing gas. Also, forexample, BCl₃ or HCl may be used as the chlorine-containing gas. Othertypes of halogen-containing gases may also be used depending onpurposes.

Also, when an SiO₂ film is to be formed, a chlorine gas may be selectedas the etching gas that can etch a part of material components includedin the first reaction gas.

As the separation gas, an inert gas such as Ar or He may be used.

In the example of FIG. 4, the separation gas supply parts 41 arrangedalong the radial direction of the rotary table 2 are connected to thesame separation gas supply source 134 and the same additive gas supplysource 135. However, the configuration of the separation gas supplyparts 41 is not limited to this example. As a variation, the separationgas supply parts 41 may be connected to different separation gas supplysources 134 and different additive gas supply sources 135. In this case,multiple separation gas supply sources 134 and multiple additive gassupply sources 135 corresponding to the separation gas supply parts 41may be provided.

The separation gas supply parts 42 formed in another one of theprotruding parts 4 may have configurations similar to the configurationsof the separation gas supply parts 41. That is, each separation gassupply part 42 may include multiple gas discharge holes 42 h and a gasintroduction port 42 a communicating with the gas discharge holes 42 h.The gas introduction port 42 a may be connected via a pipe 114 and aflow rate controller 124 to the separation gas supply source 134, andalso connected via a pipe 115 and a flow rate controller 125 to theadditive gas supply source 135.

In the present embodiment, a mixed gas including a separation gas and anadditive gas capable of controlling the adsorption of the first reactiongas is supplied from at least one of the separation gas supply parts 41provided in the separation region D1. Also, only the separation gas issupplied from the remaining separation gas supply parts 41. The mixedgas including the separation gas and the additive gas capable ofcontrolling the adsorption of the first reaction gas is supplied after areaction product is formed on the wafer W and before the first reactiongas is adsorbed onto the wafer W (or the reaction product). This makesit possible to control the adsorption of the first reaction gas.

Also in the present embodiment, a mixed gas including a separation gasand an additive gas capable of etching a part of material componentsincluded in the first reaction gas is supplied from at least one of theseparation gas supply parts 42 provided in the separation region D2.Also, only the separation gas may be supplied from the remainingseparation gas supply parts 42. The mixed gas including the separationgas and the additive gas capable of etching a part of materialcomponents included in the first reaction gas may be supplied after thefirst reaction gas is adsorbed onto the wafer W and before the firstreaction gas is caused to react with the second reaction gas. This makesit possible to control the in-plane distribution of the first reactiongas adsorbed onto the wafer W, and to control the in-plane uniformity ofthe thickness of a film of a reaction product formed on the wafer W.

FIG. 5 is a cross-sectional view of a part of the vacuum chamber 1 fromthe reaction gas nozzle 31 to the reaction gas nozzle 32. Thecross-sectional view of FIG. 5 is taken along a concentric circle of therotary table 2 of the film deposition apparatus of FIG. 1. Asillustrated in FIG. 5, each protruding part 4 is attached to the lowersurface of the top plate 11. In the vacuum chamber 1, flat and lowerceiling surfaces (first ceiling surfaces 44) are formed by the lowersurfaces of the protruding parts 4, and higher ceiling surfaces (secondceiling surfaces 45) are formed by the lower surface of the top plate11. The second ceiling surfaces 45 are located on the sides of the firstceiling surfaces 44 in the circumferential direction, and are at higherpositions than the first ceiling surfaces 44. Each of the first ceilingsurfaces 44 has a fan-like planar shape whose apex is cut off to form anarc. The gas discharge holes 42 h are formed in the middle of theprotruding part 4 in the circumferential direction, and are connected tothe gas introduction port(s) 42 a. The reaction gas nozzles 31 and 32are provided in spaces below the second ceiling surfaces 45. Thereaction gas nozzles 31 and 32 are positioned apart from the secondceiling surfaces 45 and close to the wafer W or the upper surface of therotary table 2. As illustrated in FIG. 5, the reaction gas nozzle 31 isprovided in a space 481 below the second ceiling surface 45 and on theright side of the protruding part 4, and the reaction gas nozzle 32 isprovided in a space 482 below the second ceiling surface 45 and on theleft side of the protruding part 4.

A narrow separation space H is formed between each of the first ceilingsurfaces 44 and the upper surface of the rotary table 2. When aseparation gas and/or an additive gas is supplied from the gas dischargeholes 42 h of the separation gas supply parts 42, the separation gasand/or the additive gas flows through the separation space H toward thespaces 481 and 482. In other words, the separation gas and/or theadditive gas flows along the rotational direction of the rotary table 2.Because the volume of the separation space H is less than the volumes ofthe spaces 481 and 482, the pressure in the separation space H can bekept higher than the pressures in the spaces 481 and 482 by supplyingthe separation gas and/or the additive gas. Thus, the separation space Hwith a high pressure is formed between the spaces 481 and 482. Also, theflow of the separation gas and/or the additive gas from the separationspace H into the spaces 481 and 482 functions as a counter flow to thefirst reaction gas from the first process region P1 and the secondreaction gas from the second process region P2. Accordingly, theseparation space H separates the first reaction gas from the firstprocess region P1 and the second reaction gas from the second processregion P2. This configuration prevents the first reaction gas frommixing and reacting with the second reaction gas in the vacuum chamber1.

A height h1 of the first ceiling surface 44 from the upper surface ofthe rotary table 2 is preferably determined taking into account, forexample, the pressure in the vacuum chamber 1 during a film formingprocess, the rotational speed of the rotary table 2, and/or the supplyflow rate of the separation gas and/or the additive gas so that thepressure in the separation space H becomes higher than the pressures inthe spaces 481 and 482.

A protrusion 5 (FIGS. 2 and 3) is formed on the lower surface of the topplate 11 to surround the core 21 to which the rotary table 2 is fixed.The protrusion 5 is in connection with the center-side ends of theprotruding parts 4. The lower surface of the protrusion 5 is at the sameheight as the first ceiling surfaces 44.

FIG. 1 is a cross-sectional view of the film deposition apparatus takenalong line I-I′ of FIG. 3 and illustrates a section including the secondceiling surfaces 45. FIG. 6 is a cross-sectional view of another sectionof the film deposition apparatus including the first ceiling surface 44.

As illustrated in FIG. 6, an L-shaped bent part 46 is formed at theperiphery of each of the protruding parts 4 (i.e., an end that is closerto the outer wall of the vacuum chamber 1). The bent part 46 faces theouter end face of the rotary table 2. Similarly to the protruding parts4, the bent parts 46 prevent reaction gases from entering the separationregions D1 and D2 and thereby prevent the reaction gases from beingmixed with each other. The protruding parts 4 are provided on the topplate 11, and the top plate 11 is detachable from the chamber body 12.Therefore, a small gap is provided between the outer surface of each ofthe bent parts 46 and the chamber body 12. For example, the gap betweenthe inner surface of the bent part 46 and the outer end face of therotary table 2 and the gap between the outer surface of the bent part 46and the chamber body 12 may be set at a value that is substantially thesame as the height of the first ceiling surface 44 from the uppersurface of the rotational table 2.

In each of the separation regions D1 and D2, as illustrated in FIG. 6,the inner wall of the chamber body 12 is a vertical surface that isclose to the outer surface of the bent part 46. In contrast, in regionsother than the separation regions D1 and D2, a portion of the inner wallof the chamber body 12, which extends from a position facing the outerend face of the rotary table 2 to the bottom 14, is recessed outward asillustrated in FIG. 1. The cross section of the recessed portion has asubstantially rectangular shape. In the descriptions below, the recessedportion is referred to as an evacuation region. More specifically, anevacuation region communicating with the first process region P1 isreferred to as a first evacuation region E1, and an evacuation regioncommunicating with the second process region P2 and the third processregion P3 are referred to as a second evacuation region E2. Asillustrated in FIGS. 1 through 3, a first evacuation port 610 is formedin the bottom of the first evacuation region E1, and a second evacuationport 620 is formed in the bottom of the second evacuation region E2. Asillustrated in FIG. 1, each of the first evacuation port 610 and thesecond evacuation port 620 is connected via an evacuation pipe 630 to avacuum pump 640 that is a vacuum evacuator. Also, a pressure controller650 is provided between the vacuum pump 640 and the evacuation pipe 630.

As illustrated in FIGS. 2 and 3, no separation region is providedbetween the second process region P2 and the third process region P3.However, a housing for partitioning a space above the rotary table 2 isprovided in an area in FIG. 3 where the plasma generator 80 is located.The housing defines an area where the plasma generator 80 is disposed.However, even when the plasma generator 80 is not provided, the housingis preferably provided to separate the second process region P2 and thethird process region P3. This is described in more detail later.

As illustrated in FIGS. 1 and 6, a heater unit 7 is provided in a spacebetween the rotary table 2 and the bottom 14 of the vacuum chamber 1.The heater unit 7 heats, via the rotary table 2, the wafer W on therotary table 2 to a temperature defined by a process recipe. Aring-shaped cover 71 (FIG. 6) is provided below and near the outer edgeof the rotary table 2. The cover 71 separates an atmosphere in a spaceincluding a region above the rotary table 2 and the first and secondevacuation regions E1 and E2 from an atmosphere in a space where theheater unit 7 is provided, and prevents gases from entering a regionbelow the rotary table 2. The cover 71 includes an inner part 71 a andan outer part 71 b. The inner part 71 a is provided below the rotarytable 2 and faces the outer edge of the rotary table 2 and a spacesurrounding the outer edge of the rotary table 2. The outer part 71 b isprovided between the inner part 71 a and the inner wall of the vacuumchamber 1. The outer part 71 b is disposed below the bent part 46 formedat the outer end of the protruding part 4 in each of the separationregions D1 and D2. The upper end of the outer part 71 b is positionedclose to the lower end of the bent part 46. The inner part 71 a isdisposed below the outer edge of the rotary table 2 (and below a gapsurrounding the outer edge of the rotary table 2) and surrounds theentire circumference of the heater unit 7.

A portion of the bottom 14, which is closer to the rotation center thanthe space housing the heater unit 7, protrudes upward toward the core 21and the central portion of the lower surface of the rotary table 2, andforms a protrusion 12 a. A narrow space is formed between the protrusion12 a and the core 21. Also, a narrow space is formed between therotational shaft 22 and the inner surface of a through hole formed inthe bottom 14 for the rotational shaft 22. These narrow spacescommunicate with the case 20.

A purge gas supply pipe 72 is connected to the case 20. The purge gassupply pipe 72 supplies an Ar gas as a purge gas to purge the narrowspaces. Also, purge gas supply pipes 73 are connected to the bottom 14of the vacuum chamber 1 at positions below the heater unit 7 (only onepurge gas supply pipe 73 is illustrated in FIG. 6). The purge gas supplypipes 73 are arranged in the circumferential direction at predeterminedangular intervals and used to purge the space housing the heater unit 7.

A lid 7 a is provided between the heater unit 7 and the rotary table 2to prevent entry of gases into the space housing the heater unit 7. Thelid 7 a covers an area along the circumferential direction and betweenthe inner wall of the outer part 71 b (or the upper surface of the innerpart 71 a) and the upper end of the protrusion 12 a. The lid 7 a may beformed of, for example, quartz.

A separation gas supply pipe 51 is connected to a central portion of thetop plate 11 of the vacuum chamber 1, and supplies an Ar gas as aseparation gas into a space 52 between the top plate 11 and the core 21.The separation gas supplied into the space 52 flows through a narrowspace 50 between the protrusion 5 and the rotary table 2, and flowstoward the periphery of the rotary table 2 along the upper surface ofthe rotary table 2 on which the wafer W is placed. Due to the separationgas, the pressure in the space 50 is kept higher than the pressure inthe space 481 and the space 482. Accordingly, the space 50 prevents thefirst reaction gas supplied into the first process region P1 and thesecond reaction gas supplied into the second process region P2 frompassing through a central region C and mixing with each other. That is,the space 50 (or the central region C) functions in a manner similar tothe separation spaces H (or the separation regions D1 and D2).

As illustrated in FIGS. 2 and 3, a transfer port 15 is formed in theside wall of the vacuum chamber 1. The transfer port 15 is used totransfer the wafer W between an external conveying arm 10 and the rotarytable 2. The transfer port 15 is opened and closed by a gate valve (notshown).

Elevating pins and an elevating mechanism (not shown) for lifting thewafer W are provided at a transfer position below the rotary table 2.The elevating pins pass through the recess 24 formed in the rotary table2 and push the lower surface of the wafer W upward. The wafer W istransferred between the recess 24 of the rotary table 2 and theconveying arm 10 when the recess 24 is at the transfer position facingthe transfer port 15.

Next, the plasma generator 80 is described with reference to FIGS. 7through 9. FIG. 7 is a cross-sectional view of the plasma generator 80of the film deposition apparatus of FIG. 1 taken along the radialdirection of the rotary table 2. FIG. 8 is another cross-sectional viewof the plasma generator 80 of the film deposition apparatus of FIG. 1taken along a direction that is orthogonal to the radial direction ofthe rotary table 2. FIG. 9 is a top view of the plasma generator 80 ofthe film deposition apparatus of FIG. 1. In FIGS. 7 through 9, forillustration purposes, some of the components are simplified or omitted.

Referring to FIG. 7, the plasma generator 80 includes a frame 81 formedof a high-frequency transmitting material and having a recess in theupper side, a Faraday shield plate 82, an insulating plate 83, and anantenna 85. The frame 81 is fit into an opening 11 a formed in the topplate 11. The Faraday shield plate 82 is placed in the recess of theframe 81, and has a substantially box-shape with an opening on the upperside. The insulating plate 83 is disposed on the bottom surface of theFaraday shield plate 82. The antenna 85 is supported above theinsulating plate 83. The antenna 85 is shaped like a coil that has asubstantially octagonal shape in plan view.

Multiple steps are formed in the inner surface of the opening 11 a ofthe top plate 11. A groove is formed in one of the steps along theentire circumference, and a sealing part 81 a such as an O-ring isfitted into the groove. The frame 81 includes multiple stepscorresponding to the steps of the opening 11 a. When the frame 81 isfitted into the opening 11 a, the lower surface of one of the steps ofthe frame 81 is brought into contact with the sealing part 81 a fittedinto the groove formed in one of the steps of the opening 11 a. Withthis configuration, the frame 81 is hermetically attached to the topplate 11. Also, as illustrated in FIG. 7, a pressing part 81 c isprovided along the periphery of the frame 81 fitted into the opening 11a of the top plate 11 to press the frame 81 downward or toward the topplate 11. The pressing part 81 c improves the airtightness between thetop plate 11 and the frame 81.

The lower surface of the frame 81 faces the rotary table 2 in the vacuumchamber 1. A protrusion 81 b protruding downward (or toward the rotarytable 2) is formed along the entire periphery of the lower surface ofthe frame 81. The lower end of the protrusion 81 b is positioned closeto the upper surface of the rotary table 2, and a space (which ishereafter referred to as the third process region P3) is defined abovethe rotary table 2 by the upper surface of the rotary table 2 and thelower surface of the frame 81. The distance between the lower end of theprotrusion 81 b and the upper surface of the rotary table 2 may besubstantially the same as the height h1 of the first ceiling surface 44from the upper surface of the rotary table 2 in the separation space H(FIG. 5).

The reaction gas nozzle 33 passes through the protrusion 81 b andextends in the third process region P3. In the present embodiment, asillustrated in FIG. 7, the reaction gas nozzle 33 is connected via thepipe 112 and the flow rate controller 122 to the third reaction gassupply source 132. The third reaction gas whose flow rate is controlledby the flow rate controller 122 is supplied into the third processregion P3.

Multiple gas discharge holes 35 are formed in the reaction gas nozzle 33at a predetermined interval (e.g., 10 mm) along the longitudinaldirection of the reaction gas nozzle 33. The third reaction gas isdischarged from the gas discharge holes 35. As illustrated in FIG. 8,the gas discharge holes 35 face a direction that is inclined upstream inthe rotational direction of the rotary table 2 with respect to adirection perpendicular to the upper surface of the rotary table 2.Accordingly, the reaction gas nozzle 33 discharges a gas in a directionopposite the rotational direction of the rotary table 2. Morespecifically, the reaction gas nozzle 33 discharges a gas toward a gapbetween the lower end of the protrusion 81 b and the upper surface ofthe rotary table 2. This configuration prevents a reaction gas and/or aseparation gas from flowing into the third process region P3 from aspace below the second ceiling surface 45 located upstream of the plasmagenerator 80 in the rotational direction of the rotary table 2. Also, asdescribed above, the lower end of the protrusion 81 b formed along theperiphery of the under surface of the frame 81 is positioned close tothe upper surface of the rotary table 2. This configuration makes itpossible to easily keep the pressure in the third process region P3 at ahigh level by supplying a gas from the reaction gas nozzle 33. Thisconfiguration also prevents a reaction gas and/or a separation gas fromflowing into the third process region P3.

Thus, the frame 81 includes a function to separate the third processregion P3 from the second process region P2. Thus, although the entireplasma generator 80 may not necessarily included in the film depositionapparatus of the present embodiment, the film deposition apparatuspreferably includes the frame 81 to separate the third process region P3from the second process region P2 and prevent the entry of the secondreaction gas into the third process region P3.

The Faraday shield plate 82 is formed of a conductive material such as ametal, and is grounded (not shown). As illustrated in FIG. 9, slits 82 sare formed in the bottom of the Faraday shield plate 82. Each of theslits 82 s extends in a direction that is substantially orthogonal tothe corresponding side of the antenna 85 having a substantiallyoctagonal shape in plan view.

Also, as illustrated in FIGS. 8 and 9, the Faraday shield plate 82includes two supports 82 a that are bent outward from the upper end ofthe body of the Faraday shield plate 82. The supports 82 a are supportedby the upper surface of the frame 81, and the Faraday shield plate 82 isthereby supported in a predetermined position in the frame 81.

The insulating plate 83 is formed of, for example, silica glass, has asize that is slightly smaller than the bottom surface of the Faradayshield plate 82, and is placed on the bottom surface of the Faradayshield plate 82. The insulating plate 83 insulates the Faraday shieldplate 82 and the antenna 85 from each other, while transmittinghigh-frequency waves emitted from the antenna 85 downward.

The antenna 85 is formed by winding a copper hollow pipe, for example,three times into a substantially octagonal shape in plan view. Coolingwater can be circulated through the pipe to prevent the antenna 85 frombeing heated to a high temperature due to high-frequency power suppliedto the antenna 85. The antenna 85 includes an upright part 85 a to whicha support 85 b is attached. The antenna 85 is held by the support 85 bin a predetermined position in the Faraday shield plate 82. Ahigh-frequency power supply 87 is connected via a matching box 86 to theupright part 85 a. The high-frequency power supply 87 can generatehigh-frequency power with a frequency of, for example, 13.56 MHz.

In the plasma generator 80 configured as described above, whenhigh-frequency power is supplied from the high-frequency power supply 87via the matching box 86 to the antenna 85, the antenna 85 generates anelectromagnetic field. An electric field component of theelectromagnetic field is blocked by the Faraday shield plate 82, and isnot transmitted to a lower region. Conversely, a magnetic fieldcomponent of the electromagnetic field is transmitted via the slits 82 sof the Faraday shield plate 82 into the third process region P3. Themagnetic field component activates the third reaction gas supplied at apredetermined flow rate from the reaction gas nozzle 33 into the thirdprocess region P3.

As illustrated in FIG. 1, the film deposition apparatus of the presentembodiment also includes a controller 100 implemented by a computer forcontrolling operations of the entire film deposition apparatus. A memoryof the controller 100 stores a program according to which the controller100 controls the film deposition apparatus to perform a film depositionmethod described later. The program may include steps for causing thefilm deposition apparatus to perform the film deposition method. Theprogram may be stored in a medium 102 such as a hard disk, a compactdisk, a magneto-optical disk, a memory card, or a flexible disk. Theprogram stored in the medium 102 is read by a reading device into astorage 101, and installed in the controller 100.

The controller 100 may be configured to control the flow ratecontrollers 124 and 125 for adjusting the flow rates of an additive gasand a separation gas supplied to the separation gas supply parts 41 and42. This configuration makes it possible to adjust the supply flow ratesof the additive gas and the separation gas in the radial direction ofthe rotary table 2, and thereby makes it possible to control theadsorption of the first reaction gas in the radial direction of therotary table 2. This in turn makes it possible to control the in-planeuniformity of the thickness of a film formed on the wafer W.

<Film Deposition Method>

Next, an exemplary film deposition method performed by the filmdeposition apparatus according of the present embodiment is described.In the exemplary film deposition method, it is assumed that an SiO₂ filmis formed on an inner surface of a trench formed in a silicon wafer.

In the film deposition method, it is also assumed that a material gasincluding an organic aminosilane gas is supplied from the reaction gasnozzle 31, an oxidizing gas including an O₂ gas is supplied from thereaction gas nozzle 32, and a modifying gas including an O₂ gas and anAr gas is supplied from the reaction gas nozzle 33. The modifying gassupplied from the reaction gas nozzle 33 is activated by the plasmagenerator 80. It is also assumed that five separation gas supply parts41 are arranged in the radial direction of the rotary table 2. Further,it is assumed that a separation gas including an Ar gas and an additivegas including an H₂ gas are supplied from one of the separation gassupply parts 41 that is closest to the center of the rotary table 2, andonly the separation gas including the Ar gas is supplied from the otherseparation gas supply parts 41.

First, the film deposition apparatus (or the controller 100) opens agate valve (not shown), and causes the conveying arm 10 (FIG. 3) tocarry the wafer W via the transfer port 15 into the vacuum chamber 1 andtransfer the wafer W to the recess 24 of the rotary table 2. The filmdeposition apparatus may include elevating pins (not shown) used totransfer the wafer W from the conveying arm 10 to the recess 24. Whenthe recess 24 stops at a position facing the transfer port 15, theelevating pins are caused to move up and down via through holes formedin the bottom of the recess 24 to receive the wafer W. The filmdeposition apparatus intermittently rotates the rotary table 2 andplaces the wafer W in each of five recesses 24 of the rotary table 2.

Next, the film deposition apparatus closes the gate valve and evacuatesthe vacuum chamber 1 using the vacuum pump 640 to the maximum possibledegree of vacuum. Next, the film deposition apparatus causes theseparation gas supply parts 41 and 42 to discharge an Ar gas as aseparation gas at a predetermined flow rate, and causes the separationgas supply pipe 51 and the purge gas supply pipes 72 and 73 to dischargean Ar gas at a predetermined flow rate. Then, the pressure controller650 (FIG. 1) adjusts the pressure in the vacuum chamber 1 to apredetermined process pressure. Next, the film deposition apparatusheats the wafers W using the heater unit 7 while rotating the rotarytable 2 clockwise. The rotational speed of the rotary table 2 may be setat any value depending on purposes. Also, the temperature at which thewafer W is heated by the heater unit 7 may be set at any value dependingon purposes.

After the above steps, the film deposition apparatus causes the reactiongas nozzle 31 (FIGS. 2 and 3) to supply a material gas including anorganic aminosilane gas (adsorption step), and causes the reaction gasnozzle 32 to supply an oxidizing gas including an O₂ gas (reactionstep). Also, the film deposition apparatus causes the reaction gasnozzle 33 to supply a modifying gas including an O₂ gas and an Ar gas(modification step). Further, the film deposition apparatus causes oneof the separation gas supply parts 41, which is closest to the center ofthe rotary table 2 in the radial direction, to supply an Ar gas to whichan H₂ gas is added (hydroxyl formation step).

As the rotary table 2 rotates, the wafer W repeatedly passes through thefirst process region 1, the separation region D2, the second processregion P2, the third process region P3, and the separation region D1 inthis order (see FIG. 3). Here, because five wafers W are on the rotarytable 2, processes on the respective wafers W are actually started inthe corresponding regions P1 through P3, D1, and D2. However, forbrevity, the descriptions below are based on an assumption that thewafer W first passes through the first process region P1.

When the wafer W passes through the first process region P1, thematerial gas including the organic aminosilane gas is supplied to thewafer W, and organic aminosilane is adsorbed onto the surface of thewafer W and the inner surface of a trench formed in the wafer W.

Next, the wafer W passes through the separation region D2 where theseparation gas including the Ar gas is supplied for purging, and thenpasses through the second process region P2 where the oxidizing gasincluding the O₂ gas is supplied. The O₂ gas in the oxidizing gas reactswith organic aminosilane adsorbed onto the surface of the wafer W andthe inner surface of the trench, and a molecular layer of an SiO₂ filmis formed as a reaction product. At this step, OH groups, to whichorganic aminosilane is easily adsorbed, are formed on the surface of themolecular layer of the SiO₂ film.

Next, the wafer W passes through the third process region P3 where themodifying gas including the activated O₂ gas and Ar gas is supplied. Themodifying gas including the activated O₂ gas and Ar gas easily reachesthe surface of the wafer W and an upper part (a part near the opening)of the trench, but hardly reaches an area near the bottom of the trench.Also, the modifying gas including the activated O₂ gas and Ar gas causesthe OH groups on the surface of the SiO₂ film to be desorbed.Accordingly, a part of the OH groups is desorbed from the surface of themolecular layer of the SiO₂ film formed on the surface of the wafer Wand the upper part of the trench. However, the OH groups are hardlydesorbed from the surface of the molecular layer of the SiO₂ film formednear the bottom of the trench of the wafer W. Here, the OH groupsdesorbed from the upstream side of the wafer W (a side of the wafer Wcloser to the center of the rotary table 2) spread in the downstreamdirection (toward the outer edge of the rotary table 2 in the radialdirection) along with the flow of a process gas flowing toward thesecond evacuation port 620. As a result, at a downstream position in thedirection of flow of the process gas, the OH groups may adhere again tothe surface of the molecular layer of the SiO₂ film formed on thesurface of the wafer W and the inner surface of the trench. In thiscase, the amount of the OH groups on the downstream side becomes greaterthan that on the upstream side, and the in-plane distribution of the OHgroups on the wafer W becomes uneven. Also, the OH groups spreading inthe downstream direction along with the flow of the process gas flowingtoward the second evacuation port 620 may also adhere to the surface andthe inner surface of a trench of a wafer W adjacent to the wafer W fromwhich the OH groups are desorbed. In this case, the amount of OH groupson different wafers W may become uneven.

Next, the wafer W passes through the separation region D1 where theseparation gas including the Ar gas and the additive gas including theH₂ gas are supplied. At this step, the separation gas including the Argas and the additive gas including the H₂ gas are supplied from one ofthe separation gas supply parts 41 that is closest to the center of therotary table 2 in the radial direction, and only the separation gasincluding the Ar gas is supplied from the other four separation gassupply parts 41. As a result, OH groups are selectively (locally) formedon the surface of the wafer W and the inner surface of the trench on theupstream side of the wafer W (a side closer to the center of the rotarytable 2). Here, the ratio of the supply flow rate of the H₂ gas to thesupply flow rate of the Ar gas is determined such that the amount of OHgroups formed near the bottom of the trench is maintained greater thanthe amount of OH groups formed on the upper part of the trench.

Next, the wafer W passes through the first process region P1 where thematerial gas including the organic aminosilane gas is supplied, andorganic aminosilane is adsorbed onto the molecular layer of the SiO₂film on the surface of the wafer W and the inner surface of the trench.The organic aminosilane gas is hardly adsorbed onto an area where no OHgroup is present, and easily adsorbed onto an area where OH groups arepresent. Accordingly, a greater amount of organic aminosilane isadsorbed onto an area near the bottom of the trench where a greateramount of OH groups is present. Also, OH groups are substantiallyuniformly formed on the surface of the wafer W and the upper part of thetrench. Therefore, organic aminosilane is substantially uniformlyadsorbed onto the surface of the wafer W and the upper part of thetrench.

Next, the wafer W passes through the separation region D2 where theseparation gas including the Ar gas is supplied for purging, and thenpasses through the second process region P2 where the oxidizing gasincluding the O₂ gas is supplied. The O₂ gas in the oxidizing gas reactswith organic aminosilane adsorbed onto the surface of the wafer W andthe inner surface of the trench, and a molecular layer of an SiO₂ filmis formed as a reaction product. At this step, because a greater amountof organic aminosilane is adsorbed onto an area near the bottom of thetrench, a greater amount of SiO₂ film is formed near the bottom of thetrench. This makes it possible to perform filling film formation withhigh bottom-up capability. Also, organic aminosilane is substantiallyuniformly adsorbed onto the surface of the wafer W and the upper part ofthe trench. Accordingly, an SiO₂ film with a substantially uniformthickness can be formed on the wafer W.

Thereafter, the rotary table 2 is repeatedly rotated while supplyingreaction gases. As a result, an SiO₂ film is deposited from the bottomof the trench without blocking the opening of the trench, and an SiO₂film with high in-plane uniformity is formed on the wafer W. Thus, theabove method makes it possible to fill the trench with a seamless filmwithout forming a void, and makes it possible to perform high-qualityfilling film formation. This in turn makes it possible to achieve highin-plane uniformity and high inter-plane uniformity of films.

As described above, in the film deposition method of the presentembodiment, atomic layer deposition (ALD) is performed by supplying anadditive gas capable of adjusting the amount of OH groups andcontrolling the adsorption of a material gas before the material gas isadsorbed onto the wafer W. This method makes it possible to control thein-plane uniformity and the inter-plane uniformity of the thickness offilms formed on wafers W.

Also, ALD may be performed by supplying an additive gas capable ofetching a part of a material gas and thereby adjusting the in-planedistribution of the material gas adsorbed to the wafer W after thematerial gas is adsorbed to the wafer W and before the material gas iscaused to react with an oxidizing gas. This method also makes itpossible to control the in-plane uniformity and the inter-planeuniformity of the thickness of films formed on wafers W.

<Simulation Results>

Next, results of simulations performed to study the effectiveness of thefilm deposition method and the film deposition apparatus of the presentembodiment are described with reference to FIGS. 10A through 13B. FIGS.10A through 13B are drawings illustrating flow distribution andconcentration distribution of an H₂ gas in the separation region D1.Each of FIGS. 10A, 11A, 12A, and 13A illustrates flow distribution ofthe H₂ gas, and each of FIGS. 10B, 11B, 12B, and 13B illustratesconcentration distribution of the H₂ gas.

In each of the simulations, an Ar gas and a small amount of H₂ gas aresupplied from one of five separation gas supply parts 41-1 through 41-5arranged along the radial direction of the rotary table 2, only the Argas is supplied from the other four separation gas supply parts 41, andthe flow distribution and the concentration distribution of the H₂ gasare observed.

FIGS. 10A and 10B illustrate the flow distribution and the concentrationdistribution of the H₂ gas observed when the Ar gas and the H₂ gas aresupplied from the separation gas supply part 41-1 that is closest to thecenter of the rotary table 2, and only the Ar gas is supplied from theother separation gas supply parts 41-2 through 41-5. The flow rates ofthe H₂ gas and the Ar gas supplied from the separation gas supply part41-1 are 0.2 sccm and 1 slm, respectively; and the flow rate of the Argas supplied from each of the separation gas supply parts 41-2 through41-5 is 1 slm.

As illustrated by FIG. 10A, the H₂ gas supplied from the separation gassupply part 41-1 flows in the separation region D1 (separation space H),which is a narrow space, along the rotational direction of the rotarytable 2. Also, as illustrated by FIG. 10B, the concentration of the H₂gas supplied from the separation gas supply part 41-1 is high in an areain the radial direction of the rotary table 2 where the separation gassupply part 41-1 is provided. Thus, by supplying the H₂ gas and the Argas form the separation gas supply part 41-1, it is possible toselectively (or locally) supply the H₂ gas to an area in the radialdirection of the rotary table 2 where the separation gas supply part41-1 is provided.

FIGS. 11A and 11B illustrate the flow distribution and the concentrationdistribution of the H₂ gas observed when the Ar gas and the H₂ gas aresupplied from the separation gas supply part 41-2 that is second closestto the center of the rotary table 2, and only the Ar gas is suppliedfrom the other separation gas supply parts 41-1 and 41-3 through 41-5.The flow rates of the H₂ gas and the Ar gas supplied from the separationgas supply part 41-2 are 0.2 sccm and 1 slm, respectively; and the flowrate of the Ar gas supplied from each of the separation gas supply parts41-1 and 41-3 through 41-5 is 1 slm.

As illustrated by FIG. 11A, the H₂ gas supplied from the separation gassupply part 41-2 flows in the separation region D1 (separation space H),which is a narrow space, along the rotational direction of the rotarytable 2. Also, as illustrated by FIG. 11B, the concentration of the H₂gas supplied from the separation gas supply part 41-2 is high in an areain the radial direction of the rotary table 2 where the separation gassupply part 41-2 is provided. Thus, by supplying the H₂ gas and the Argas form the separation gas supply part 41-2, it is possible toselectively (or locally) supply the H₂ gas to an area in the radialdirection of the rotary table 2 where the separation gas supply part41-2 is provided.

FIGS. 12A and 12B illustrate the flow distribution and the concentrationdistribution of the H₂ gas observed when the Ar gas and the H₂ gas aresupplied from the separation gas supply part 41-3 that is third closestto the center of the rotary table 3, and only the Ar gas is suppliedfrom the other separation gas supply parts 41-1, 41-2, 41-4, and 41-5.The flow rates of the H₂ gas and the Ar gas supplied from the separationgas supply part 41-3 are 0.2 sccm and 1 slm, respectively; the flow rateof the Ar gas supplied from each of the separation gas supply parts 41-1and 41-2 is 2 slm; and the flow rate of the Ar gas supplied from each ofthe separation gas supply parts 41-4 and 41-5 is 4 slm.

As illustrated by FIG. 12A, the H₂ gas supplied from the separation gassupply part 41-3 flows in the separation region D1 (separation space H),which is a narrow space, along the rotational direction of the rotarytable 2. Also, as illustrated by FIG. 12B, the concentration of the H₂gas supplied from the separation gas supply part 41-3 is high in an areain the radial direction of the rotary table 2 where the separation gassupply part 41-3 is provided. Thus, by supplying the H₂ gas and the Argas form the separation gas supply part 41-3, it is possible toselectively (or locally) supply the H₂ gas to an area in the radialdirection of the rotary table 2 where the separation gas supply part41-3 is provided. In the example of FIGS. 12A and 12B, the flow rate ofthe Ar gas supplied from each of the separation gas supply parts 41-4and 41-5 is set at a value that is greater than the flow rate of the Argas supplied from each of the separation gas supply parts 41-1 and 41-2.With this configuration, the flow of the H₂ gas form the separation gassupply part 41-3 toward the outer edge of the rotary table 2 in theradial direction is blocked by the flow of the Ar gas supplied at a highflow rate from the separation gas supply parts 41-4 and 41-5.Accordingly, most of the H₂ gas supplied from the separation gas supplypart 41-3 flows in the rotational direction of the rotary table 2. Thus,it is possible to more selectively (or locally) supply the H₂ gas byadjusting the flow rates of the Ar gas supplied from the separation gassupply parts 41-1, 41-2, 41-4, and 41-5 that supply only the Ar gas.

FIGS. 13A and 13B illustrate the flow distribution and the concentrationdistribution of the H₂ gas observed when the Ar gas and the H₂ gas aresupplied from the separation gas supply part 41-4 that is fourth closestto the center of the rotary table 4, and only the Ar gas is suppliedfrom the other separation gas supply parts 41-1 through 41-3 and 41-5.The flow rates of the H₂ gas and the Ar gas supplied from the separationgas supply part 41-4 are 0.2 sccm and 1 slm, respectively; and the flowrate of the Ar gas supplied from each of the separation gas supply parts41-1 through 41-3 and 41-5 is 1 slm.

As illustrated by FIG. 13A, the H₂ gas supplied from the separation gassupply part 41-4 flows in the separation region D1 (separation space H),which is a narrow space, along the rotational direction of the rotarytable 2. Also, as illustrated by FIG. 13B, the concentration of the H₂gas supplied from the separation gas supply part 41-4 is high in an areain the radial direction of the rotary table 2 where the separation gassupply part 41-4 is provided. Thus, by supplying the H₂ gas and the Argas form the separation gas supply part 41-4, it is possible toselectively (or locally) supply the H₂ gas to an area in the radialdirection of the rotary table 2 where the separation gas supply part41-4 is provided.

<Results of Experiment>

Next, results of an experiment indicating the effectiveness of the filmdeposition method and the film deposition apparatus of the presentembodiment are described. FIG. 14 is a graph illustrating a relationshipbetween the supply flow rate of an H₂ gas and the thickness of an SiO₂film formed on a wafer.

This experiment was performed to confirm whether the adsorption of anorganic aminosilane gas would be improved (whether the adsorptioninhibition property would be reduced) by supplying an H₂ gas to a waferwithout activating the H₂ gas. In the experiment, the H₂ gas wassupplied at supply flow rates of 0 sccm, 6 sccm, 100 sccm, and 200 sccm,and the thickness of the SiO₂ film in each case was measured todetermine the relationship between the supply flow rate of the H₂ gasand the thickness of the SiO₂ film formed on the wafer.

More specifically, an SiO₂ film was formed by supplying an organicaminosilane gas, a mixed gas of an activated Ar gas and an activated O₂gas, and a non-activated H₂ gas in this order to the surface of thewafer W. Here, the organic aminosilane gas is an example of a firstreaction gas, the mixed gas of the Ar gas and the O₂ gas is an exampleof a second reaction gas, and the H₂ gas is an example of an additivegas.

As indicated by FIG. 14, the thickness of the SiO₂ film formed on thewafer W is increased by supplying the non-activated H₂ gas aftersupplying the mixed gas of the activated Ar gas and the activated O₂ gasand before supplying the organic aminosilane gas. Also, the thickness ofthe SiO₂ film increases as the supply flow rate of the H₂ gas increases.As the results indicate, the adsorption of the organic aminosilane gascan be improved by supplying the non-activated H₂ gas after supplyingthe mixed gas of the activated Ar gas and the activated O₂ gas andbefore supplying the organic aminosilane gas.

Based on the above characteristics, the film deposition apparatus of thepresent embodiment controls the thickness of a film formed on the waferW in the diametral direction of the wafer W by changing the amount ofthe H₂ gas added to the Ar gas depending on positions in the radialdirection of the rotary table 2 (or the diametral direction of the waferW). Thus, the present embodiment can improve the in-plane uniformity ofthe thickness of a film formed on the wafer W.

In the above embodiment, the reaction gas nozzle 31 is an example of afirst reaction gas supply part, the reaction gas nozzle 32 is an exampleof a second reaction gas supply part, and the reaction gas nozzle 33 isan example of a third reaction gas supply part.

A film deposition apparatus and a film deposition method according tothe embodiments of the present invention are described above. However,the present invention is not limited to the specifically disclosedembodiments, and variations and modifications may be made withoutdeparting from the scope of the present invention.

For example, although an SiO₂ film is formed to fill a trench formed inthe wafer W in the above embodiment, an SiO₂ film may be formed to filla via formed in the wafer W. Also, an SiO₂ film may be formed on asurface of the wafer W where recesses such as a trench and a via are notformed.

An aspect of this disclosure provides a film deposition apparatus thatcan control the in-plane uniformity of the thickness of a film formed ona substrate.

What is claimed is:
 1. A film deposition apparatus, comprising: aprocess chamber; a rotary table that is disposed in the process chamberand includes an upper surface for holding a substrate; a first reactiongas supply part that is disposed in a first process region above therotary table and configured to supply a first reaction gas to the uppersurface of the rotary table; a second reaction gas supply part that isdisposed in a second process region apart from the first reaction gassupply part in a circumferential direction of the rotary table andconfigured to supply a second reaction gas, which reacts with the secondreaction gas, to the upper surface of the rotary table; and separationgas supply parts that are disposed in a separation region between thefirst reaction gas supply part and the second reaction gas supply partin the circumferential direction of the rotary table and configured tosupply a separation gas for separating the first reaction gas and thesecond reaction gas, the separation gas supply parts being arranged atpredetermined intervals along a radial direction of the rotary table,wherein the separation gas supply parts are configured to supply, inaddition to the separation gas, an additive gas for controllingadsorption of the first reaction gas or for etching a part of materialcomponents included in the first reaction gas.
 2. The film depositionapparatus as claimed in claim 1, wherein each of the separation gassupply parts includes gas discharge holes that are arranged in theradial direction of the rotary table and supply the separation gas andthe additive gas to the upper surface of the rotary table.
 3. The filmdeposition apparatus as claimed in claim 1, wherein the separation gassupply parts are disposed in a same position in a rotational directionof the rotary table.
 4. The film deposition apparatus as claimed inclaim 1, wherein the separation gas supply parts are disposed indifferent positions in a rotational direction of the rotary table. 5.The film deposition apparatus as claimed in claim 1, wherein the firstprocess region is defined by the upper surface of the rotary table and afirst ceiling surface of the process chamber; the second process regionis defined by the upper surface of the rotary table and a second ceilingsurface of the process chamber; the separation region is defined by theupper surface of the rotary table and a third ceiling surface of theprocess chamber; and a height of the third ceiling surface from theupper surface of the rotary table is less than heights of the firstceiling surface and the second ceiling surface from the upper surface ofthe rotary table.
 6. The film deposition apparatus as claimed in claim1, further comprising: flow rate controllers provided for each of theseparation gas supply parts and configured to control supply flow ratesof the separation gas and the additive gas.
 7. The film depositionapparatus as claimed in claim 1, wherein the first process region, thesecond process region, and the separation region are arranged in thisorder in a rotational direction of the rotary table; and the separationgas supply parts are configured to supply the additive gas forcontrolling the adsorption of the first reaction gas.
 8. The filmdeposition apparatus as claimed in claim 7, wherein the separation gassupply parts are configured to supply a hydrogen-containing gas as theadditive gas.
 9. The film deposition apparatus as claimed in claim 7,wherein the separation gas supply parts are configured to supply ahalogen-containing gas as the additive gas.
 10. The film depositionapparatus as claimed in claim 1, wherein the first process region, theseparation region, and the second process region are arranged in thisorder in a rotational direction of the rotary table; and the separationgas supply parts are configured to supply the additive gas for etching apart of the material components included in the first reaction gas. 11.The film deposition apparatus as claimed in claim 10, wherein the firstreaction gas supply part is configured to supply a silicon-containinggas as the first reaction gas; and the separation gas supply parts areconfigured to supply a chlorine gas as the additive gas.
 12. The filmdeposition apparatus as claimed in claim 1, wherein the second reactiongas supply part is configured to supply an oxidizing gas or a nitridinggas as the second reaction gas.
 13. The film deposition apparatus asclaimed in claim 1, further comprising: a third reaction gas supply partthat is disposed in a third process region apart from the first reactiongas supply part and the second reaction gas supply part in thecircumferential direction of the rotary table and configured to supply,to the upper surface of the rotary table, a third reaction gas formodifying a reaction product formed as a result of reaction between thefirst reaction gas and the second reaction gas.
 14. The film depositionapparatus as claimed in claim 13, further comprising: a plasma generatorthat is disposed above the third process region and configured toactivate the third reaction gas.
 15. The film deposition apparatus asclaimed in claim 1, wherein the substrate is a wafer having a surface inwhich a recess is formed.
 16. The film deposition apparatus as claimedin claim 15, wherein the recess is a trench or a via formed in thesurface of the wafer.